E-readers

What e-readers are

An e-reader is built for one job: reading e-books and periodicals. Unlike a tablet or phone, it usually has an electronic-paper screen instead of a backlit one.

• A paper-like screen: E-paper is not backlit; Wikipedia notes it causes no more eye strain than a printed book.
• A library in a pocket: Thousands of books fit in the space of one; Kobo rates 16GB at about 12,000 eBooks.
• Nothing to distract: Amazon points out that a Kindle has no notifications, email or social media.
• Tied to a store: Most e-readers link to one bookstore: Kindles to Amazon’s Kindle Store, Kobos to the Kobo Store.
• Who makes them: Amazon makes the Kindle and Rakuten the Kobo; Onyx Boox sells Android-based models.

How they work

Most e-readers use E Ink, a display developed at MIT. Tiny capsules hold charged white and black pigments, and an electric field moves them to draw each pixel.

• Power only to change: The picture stays with no power, so the screen uses energy only to turn a page or run the light.
• A front light: A built-in light shines onto the screen for reading in the dark; Amazon’s first Paperwhite added an LED front light in 2012.
• Warm light: Kobo’s ComfortLight PRO and the Kindle Paperwhite shift the light from white toward amber to cut blue light at night.
• A color filter: Color screens such as E Ink Kaleido 3 add a color filter layer over a grayscale panel; E Ink rates it at 4,096 colors.
• Two sharpness levels: Kaleido 3 shows black-and-white text at 300 ppi but color at 150 ppi.
• Wi-Fi and Bluetooth: Wi-Fi downloads books; Bluetooth lets Kobo models play audiobooks through wireless headphones.

Types

• Black-and-white readers: 6–7″ E Ink screens at 300 ppi for text, such as the Kindle, Kindle Paperwhite and Kobo Clara BW.
• Color readers: Color E Ink for covers, comics and highlights, such as the Kobo Clara Colour, Kobo Libra Colour and Kindle Colorsoft.
• Readers with buttons: Physical page-turn buttons, as on the Kobo Libra Colour; Amazon sells a magnetic page-turn cover for the new Paperwhite and Colorsoft.
• Writing tablets: Larger E Ink slates with a stylus for notes, such as the Kindle Scribe, first released in 2022, and the Kobo Elipsa 2E.
• Android e-readers: Onyx Boox models run Android, so reading apps from other stores can be installed.
• Phone-shaped readers: Pocket models such as the Boox Palma 2 Pro; Engadget notes it takes a data-only 5G SIM.

What to look for

• Size and weight: The 6″ Kindle weighs 140 g and the 6″ Kobo Clara models 174 g; 7″ models run from 199.5 g to 229 g.
• Sharp text: 300 ppi makes text look printed; on Kaleido 3 color screens, color drops to 150 ppi.
• Waterproofing: IPX8 models are rated for 60 minutes in 2 meters of fresh water; Tom’s Guide lists the 2026 base Kindle as not waterproof.
• Battery claims: Makers quote 6 to 12 weeks for Kindles and 40 to 53 days for Kobos, based on about 30 minutes of reading a day.
• File formats: Kobos open EPUB and 14 other formats natively; Kindles can’t display EPUB natively and use Amazon’s formats, such as AZW and KFX.
• Library borrowing: Kobos borrow through Libby built in; Libby can send books to a Kindle only for U.S. libraries.
• Storage: Kobo counts 32GB as about 24,000 eBooks or 150 audiobooks.

On the plane and on the trip

• At the checkpoint: TSA asks travelers to take e-readers out of the carry-on and place them alone in a bin for X-ray screening.
• Carry-on is best: The FAA says devices with lithium batteries should travel in carry-on bags; in checked bags they must be fully off and protected.
• Gate to gate: Since October 31, 2013, the FAA has let airlines allow e-readers at all altitudes; each airline decides, and devices go in airplane mode.
• Wireless on board: Amazon says FAA rules require crew permission before using a Kindle’s wireless connection in flight.
• Reading offline: Libby lets you download library books for offline reading, with no Wi-Fi needed in the air.
• Library access abroad: Kobo notes that OverDrive, Libby and Kobo Audiobooks work only in select countries.
• Pool and beach: After a dip in salt or chlorinated water, Amazon says to rinse the Kindle in fresh water, drain it port-down and let it dry before charging.

Limits and care

• Softer color: Amazon notes the Colorsoft’s color filter layer makes its screen look different in texture and brightness from a Paperwhite.
• Not for underwater: Amazon says Kindles are not meant for underwater use and should be kept from seawater, pools, steam rooms and pressurized water.
• Drops break the seal: Amazon warns that a drop or other damage can compromise a Kindle’s waterproofing.
• No heat to dry: Never dry an e-reader with a hair dryer or microwave, or push a cotton swab into the USB-C port, Amazon says.
• Built to be fixed: New Kindles have a battery that can be swapped through the back panel; Kobo says its Clara and Libra models are repairable.

A short history

Early commercial e-readers included Sony’s Data Discman and the Rocket eBook. E Ink Corporation was founded in 1997 by MIT students and researchers.

• 2004: Sony’s Librie becomes the first e-reader with an electronic-paper screen.
• November 19, 2007: Amazon releases the first Kindle; it sells out within five and a half hours.
• May 1, 2010: Kobo releases its first eReader; Rakuten completes its purchase of Kobo in January 2012.
• October 1, 2012: The first Kindle Paperwhite brings a built-in LED front light.
• April 30, 2024: Kobo releases the Clara Colour and Libra Colour, with E Ink Kaleido 3 color screens.
• October 30, 2024: Amazon releases its first color Kindle, the Kindle Colorsoft Signature Edition.
• October 1, 2026: Amazon unveils a thinner Kindle, Kindle Paperwhite and Kindle Colorsoft with flush-front screens.